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a part of the amniotic sac that sometimes envelops the head of the fetus at birth.
an areolar, four-layer peritoneal fold, formed by the double-layer dorsal mesentery of the stomach (dorsal mesogastrium) descending from the greater curvature of the stomach to fold under on itself and ascend to the transverse colon; the descending and ascending portions fuse, obliterating the inferior recess of the omental bursa, resulting in the four-layer structure that usually hangs over the anterior aspect of the intestines like an apron; components include the following peritoneal ligaments: gastrophrenic, gastrosplenic, splenorenal, and gastrocolic.
n. pl. pi·lei (-lē-ī′)
1. Botany The umbrellalike fruiting structure forming the top of a stalked fleshy fungus, such as a mushroom; the cap.
2. A brimless round skullcap worn by ancient Romans.
3. See caul.